Giardia species are a group of endoparasites that inhabit the intestinal tract and may cause clinical or subclinical infections in mammals. Detection and identification of Giardia spp. by light microscopy can be difficult or unreliable due to the sporadic shedding of cysts, inadequate numbers of organisms, improper specimen collection or the interference of anti-diarrheal medication. Commercial kits utilizing ELISA and immunofluorescent antibody (FA) technologies have recently become available for the diagnosis of human giardiasis. We report here data on the efficacy of two such kits in detecting Giardia infections in hamsters and mice. Samples from 43 hamsters and 35 mice known to be infected with Giardia spp. as determined by fecal/cecal microscopic examinations were tested utilizing ELISA and FA serological kits. Both kits yielded positive results with hamsters but neither were able to detect Giardia muris in infected mice. Substitution of a specific anti-Giardia muris monoclonal antibody in the FA kit yielded positive results in mice and hamsters but was negative for Giardia lamblia from human samples. Fecal samples from 8 day old hamsters were positive using the FA test kit while the ELISA test became positive at day 15, indicating an increased sensitivity of the FA kit. Thus, ELISA and FA assays could be a valuable adjunct to the examination for intestinal giardiasis as they can be performed quickly using non-infective formalin fixed fecal material. The ability to detect Giardia infection depends on the antigenic make up among different Giardia and the sensitivity of the individual test.